The present invention relates to cosmetic hair compositions comprising a combination of at least one cationic polymer and at least one nonionic associative polymer, as well as to their use as conditioners in particular.
The importance of cationic polymers as cosmetic components for treating and protecting the hair has been known for a long time. By virtue of their considerable substantivity for the hair, they improve the hair""s cosmetic properties. However, in the field of hair care, cationic polymers have never been able to advantageously replace cationic surfactants of quaternary ammonium type, which give better quality performance in cosmetic terms but most of them have a certain number of problems such as less than perfect eye tolerance and appreciable environmental toxicity.
Moreover, surfactants of quaternary ammonium type in combination with fatty alcohols are conventionally used to thicken conditioners. However, these thick emulsions have the cumulative drawbacks of their constituents, namely the problems described above due to the presence of cationic surfactants and an effect of making the hair feel lank by depositing fatty alcohols.
The use of conventional thickeners, i.e. water-soluble polymers, has hitherto not made it possible to obtain satisfactory rheological properties. These formulations are often too runny and sticky when the desired level of viscosity is reached.
One very advantageous recent approach consisted in using, as thickeners, polymers capable of associating reversibly with each other or with other molecules. Such polymers are known as xe2x80x9cassociative polymersxe2x80x9d. One specific case of associative polymers is amphiphilic polymers, i.e. polymers comprising one or more hydrophilic portions which make them soluble in water, and one or more hydrophobic regions via which the polymers interact and assemble with each other or with other components.
It is known practice to prepare hair compositions in the form of a gel using, as a thickening system, such associative amphiphilic polymers, in conjunction with surfactants. It is thought that the advantageous rheological properties of the gels thus obtained result from the formation of mixed micelles formed from the surfactants and the hydrophobic portions of the amphiphilic polymers, these micelles constituting a multitude of physical crosslinking points.
European patent application EP-A-0,415,705 describes a thickening system for rinse-out conditioners consisting of a first thickener which is a water-soluble polymer modified with C8-C22 hydrophobic groups, and a secondary thickener which is a water-soluble polymer with a molar mass of greater than about 20,000.
The Applicant has now discovered that the combination of a certain type of cationic polymer which has advantageous cosmetic properties with a nonionic associative polymer makes it possible not only to obtain thickened formulations which have a very pleasant texture, but also to improve the cosmetic performance quality of the cationic polymer.
A subject of the present invention is consequently a cosmetic composition comprising, in a cosmetically acceptable medium, at least one cationic polymer containing at least one acrylamide unit or acrylamide derivative and at least one nonionic associative polymer containing at least one fatty chain.
Another subject of the present invention is the use of a cationic polymer containing at least one acrylamide unit or acrylamide derivative in combination with at least one nonionic associative polymer containing at least one fatty chain, for thickening a cosmetically acceptable medium.
A third subject of the invention is a cosmetic process for treating the hair with the cosmetic compositions thickened by the combination of a cationic polymer containing at least one acrylamide unit or acrylamide derivative and at least one nonionic associative polymer containing at least one fatty chain.
Other subjects will become apparent on reading the description and the examples which follow.
The cosmetic compositions in accordance with the invention are essentially characterized in that they contain, in a cosmetically acceptable support, (A) at least one cationic polymer containing at least one acrylamide unit or acrylamide derivative, and (B) at least one nonionic associative polymer containing at least one fatty chain.
The cationic polymers used as component (A) in the compositions of the invention are preferably polymers comprising at least one unit of type I and at least one unit of type II or IIxe2x80x2 or III or IIIxe2x80x2 corresponding to the formulae below: 
in which
R1 represents a hydrogen atom or a methyl group,
B represents a group A or a group NH-A,
A represents a C1-C6 alkylene group,
R2, R3 and R4 represent, independently of each other, a C1-C6 alkyl group,
R5 and R6 represent, independently of each other, a hydrogen atom or a C1-C6 alkyl group,
R7 and R8, independently of each other, denote an alkyl group containing from 1 to 22 carbon atoms, a hydroxyalkyl group in which the alkyl group preferably contains from 1 to 5 carbon atoms, or a lower amidoalkyl group (1 to 5 carbon atoms), or R7 and R8 can denote, together with the nitrogen atom to which they are attached, a heterocyclic group such as piperidyl or morpholinyl,
k and t are equal to 0 or 1, the sum (k+t) being equal to 1, and
Xxe2x88x92 represents an organic or inorganic anion.
According to the invention, the expression xe2x80x9clower C1-C6 alkyl groupxe2x80x9d means an alkyl group containing a linear or branched chain comprising from 1 to 6 carbon atoms, such as methyl, ethyl, n-propyl, n-butyl, n-pentyl and n-hexyl radicals, as well as the corresponding branched isomers.
According to the invention, the expression xe2x80x9cC1-C6 alkylene groupxe2x80x9d means a group chosen from methylene, ethylene, 1,3-propylene, 1,4-butylene, 1,5-pentylene and 1,6-hexylene groups, or the branched isomers thereof.
In one preferred embodiment of the invention, a cationic copolymer is used comprising at least one unit of type I and one unit of type II.
In an even more particularly preferred embodiment of the invention, a cationic copolymer is used comprising at least one unit of type I and one unit of type II above in which R1 represents a methyl group, B represents an ethylene group, R2, R3 and R4 each represent a methyl group, R5 and R6 each represent a hydrogen atom and Xxe2x88x92 is a chloride ion.
A poly(dimethyldiallylammonium chloride/acrylamide) copolymer sold under the name Merquat(copyright) 550 by the company Calgon can be used as cationic polymer of the invention.
Preferred examples of cationic polymers used as component (A) are a crosslinked copolymer of trimethylammonioethyl methacrylate chloride and acrylamide sold by the company Allied Colloids under the name Salcare(copyright) SC 92, a non-crosslinked copolymer of trimethylammonioethyl methacrylate chloride and acrylamide, sold under the name Bina Quat(copyright) P100 by the company Ciba Geigy, under the name Polytec(copyright) 95 by the company Polytec, and under the name Nalquat(copyright) by the company Nalco, and a non-crosslinked copolymer of trimethylammonioethyl methacrylate chloride and methacrylamide, sold under the name Rohagit KF(copyright) 720F by the company Rohm. Even more preferably, the polymer Salcare(copyright) SC 92 will be used.
In accordance with the invention, the expression xe2x80x9cassociative polymersxe2x80x9d means amphiphilic polymers comprising hydrophilic portions and hydrophobic regions which, in aqueous medium, will have a tendency to assemble with each other or with other molecules. These hydrophobic portions can be, for example, side fatty chains or terminal fatty chains introduced by copolymerization or by grafting, or alternatively they form part of the main chain of the polymer.
The nonionic amphiphilic polymers according to the present invention, which are used as component (B), are preferably chosen from:
(1) celluloses modified with groups comprising at least one C8-C22 fatty chain, for example
hydroxyethylcellulose modified with groups comprising at least one C8-C22 fatty chain. Such a product is, for example, Natrosol Plus Grade 330 (C16 alkyl chains), sold by the company Aqualon, or alternatively Bermocoll EHM 100 sold by the company Berol Nobel; or
celluloses modified with alkylphenyl polyalkylene glycol ether groups, such as the product Amercell Polymer(copyright) HM-1500 sold by the company Amerchol;
(2) hydroxypropyl guars modified with groups comprising at least one C8-C22 fatty chain, such as the product Esaflor(copyright) HM 22 sold by the company Lamberti, and the products Miracare(copyright) XC95-3 and RE205-1 sold by the company Rhxc3x4ne Poulenc;
(3) polyurethanes comprising at least one C8-C22 fatty chain, such as the products Dapral(copyright)T210 and Dapral(copyright)T212, sold by the company Akzo, or the products Acrysol(copyright)46 and DW 1206 F sold by the company Rohm and Haas;
(4) copolymers of vinylpyrrolidone and hydrophobic monomers containing a C8-C22 fatty chain, such as, for example, the products Antaron(copyright) V216, Antaron(copyright) V220, Ganex(copyright) V261 and Ganex(copyright) V220 sold by the company ISP;
(5) copolymers of C1-C6 alkyl methacrylates or acrylates and amphiphilic monomers comprising at least one C8-C22 fatty chain, such as, for example, the oxyethylenated methyl methacrylate/stearyl acrylate copolymer sold by the company Goldschmidt under the name Antil(copyright) 208;
(6) copolymers of hydrophilic methacrylates or acrylates and hydrophobic monomers comprising at least one C8-C22 fatty chain, such as, for example, the copolymer of polyethylene glycol methacrylate/lauryl methacrylate.
(7) fatty-chain starches,
(8) fatty-chain proteins.
The cationic polymers and the nonionic associative polymers of the present invention are used in the compositions of the invention in amounts which are sufficient to obtain a satisfactory thickening of the aqueous medium, thus allowing the composition to be applied and distributed uniformly on the hair. Such a composition has a viscosity of between 100 centipoises (cP) and 100 poises (P), preferably between 200 centipoises (cP) and 50 poises (P).
An amount of cationic polymer of between 0.05 and 10% by weight, preferably between 0.1 and 5% by weight, of active material relative to the total weight of the composition is used in particular.
The nonionic associative polymers used in the present invention are present in a proportion of from 0.05 to 10% by weight, preferably in a proportion of from 0.1 to 5% by weight, of active material relative to the total weight of these composition.
The cosmetically acceptable medium preferably consists of water and can also contain cosmetically acceptable solvents, for example lower monoalcohols such as ethanol or isopropanol, glycols such as diethylene glycol, glycol ethers such as ethylene glycol alkyl ether or diethylene glycol alkyl ether, or alternatively fatty acid esters, these solvents being used alone or in the form of a mixture.
The cosmetic hair compositions of the present invention can also contain one or more commonly used additives. Examples which may be mentioned are fatty alcohols, fatty acid esters of fatty alcohols, fragrances, dyes, preserving agents, sunscreens, proteins, alkylated proteins, quaternized proteins, vitamins and provitamins, pH regulators, anionic, cationic, nonionic or amphoteric surfactants, silicones, volatile silicones, silicone oils, silicone gums, amino silicones, quaternized silicones, alkylated silicones, grafted silicones, silicone emulsions, mineral and plant oils, plant waxes, ceramides or pseudoceramides and polymers other than those according to the invention defined above. It is clearly understood that the choice of these compounds must take into account any interactions with the thickening system. A person skilled in the art will take care to ensure that the addition of these additives does not have an adverse effect on the advantageous properties of the compositions obtained according to the present invention.
One cosmetic process for treating the hair according to the invention consists in applying a cosmetic composition defined above to the hair, in distributing it homogeneously and, after leaving it on the hair for a suitable period, in optionally rinsing and then drying the hair thus treated.
The examples which follow are intended to illustrate the invention without thereby being limiting in nature.